Theoretical Analysis And Project Application Study On Ground Exchangers Of Ground-Source Heat Pump Systems

Energy saving and environmental protection are always two prevailing problems since last century. As a result, the investigation and application of low-cost, nonpolluting and renewable energy engineering technique are widely concerned. In this paper, a novel technique of air-conditioning, ground-source heat pump is mainly discussed, based on the existing research developments. It brings forward a new way to the energy saving and environmental protection of air-conditioning systems. The main research contents of this paper are as following:1. Based on the analysis of existing heat transfer models, design methods and experiences of the ground loop heat exchangers, a computer-aided design software is proposed. It can be used to design the horizontal loop, vertical loop and double-pipe heat exchangers. The main structure, functions and calculation methods of the software are discussed in detail. It is proved that the application of the computer-aided design can improve the calculation precision, and shorten the design period.2. The integrated system combined radiant floor with ground-source heat pump is discussed. The basic theory, various operating and controlling models of the system are described. Based on the theory of this integrated system, a new air-conditioning system applied to the villadom is designed. The calculation and design procedures of airconditioning load, ground loop heat exchangers, radiant floor system, distribution system between heat pump and build are mainly introduced. An array of benefits is provided with the application of the integrated system, such as high COP&SPF, energy saving, small fluctuation with the ambient temperature, improving the conflict between the fresh air supply and energy consumption and etc.3. A comparison has been made on ground-source heat pump (GSHP) with the air-source heat pump (ASHP). Two main categories of ground-source heat pumps (horizontal and vertical) are analyzed technically and economically. Monthly heating/cooling capacities and coefficients of performance for air-source and vertical and horizontal ground-source systems are calculated. The desired type of heat exchanger is determined by considering economic factors such as the total costs, comprised of the capital and operating costs. The cost-effectiveness of investments of each system is discussed, with parameters, such as the payback period, net present value and internal rate of return. It is concluded that the ground-source heat pumps have the potential to reduce peak demands and total electricity consumption, thus offer better techno-economic viability.